Balls and Strikes still vary by umpire ... more than 2 to 1.

The graph above:
- vertical: percent of total innings for each umpire in 2015
- horizontal: Strike Outs divided by non-intentional walks.

In the baseball-reference.com link above there are four groups of umpires. The groups are not labeled. I did a copy and paste of all four into a spreadsheet. The total umpire innings in the spreadsheet was 42,883.5. I based umpire innings percent on that. Unfortunately, baseball-reference.com represents inning portions as .1 and .2, not as .333 and .666, which would make the arithmetic work. The total innings shown on the web page is 43,407.2, really 43,407.666. I found 90 umpires. So even if each umpire's innings were off by a full inning that still would not account for the discrepancy of about 514.

Obviously, the umpires who work the most innings, favor the pitchers the most, i.e., they have the highest SO to BB ratio. Those who work the fewest innings, tend to favor the batters. That might be a reflection of age. Older umpires may get the most innings based on seniority.

How about my idea of a fixed bull's eye target? If the pitch hits it, it's a strike. Eliminate the catcher and get both the catcher and plate umpire out of harm's way. Base runners may not leave until the ball is hit with a bat.